The raw sewage discharged from the human body is typically discharged to a sewage system by use of a flush toilet and the like in an ordinary house or is discharged into a river after being temporarily stored in a holding tank and purified therein. However, at events such as festivals, athletic events, fairs, meetings and the like, temporary toilet facilities must be provided to dispose of the raw sewage.
Employed conventionally are movable temporary toilets, most of which have a tank for temporarily accommodating raw sewage therein. However, the temporary toilet has a problem in that the raw sewage stored in the tank is sucked into a vacuum truck for collection, which is laborious and time consuming for maintenance thereof after use of them.
Transportation vehicles such as buses, trains, vessels, etc. which operate over long distances are provided with an exclusive tank for storing and holding the discharged raw sewage. The raw sewage in this tank is subjected to a deodorizing treatment by chemicals, and thereafter collected by a vacuum truck.
In facilities of the above type, the raw sewage is stored in the state as discharged from the human body, and thereafter collected so that disposal of the raw sewage is unhygienic. Also,, a long period of use of the tank creates sewage residue on the tank which causes a bad smell which is disliked by an operator. Thus, such temporary sewage facilities are not preferable in modern times.
In an attempt to improve on the above, there have been proposed several hygienic proposal methods. In one method, for example, chemicals are introduced into the tank where the raw sewage is stored to thereby prevent the bad smell and effect a sterilization. This is mainly employed in the transportation industry such as on trains like the Shinkansen Express in Japan. This method, however, cannot be used for a long period of time because the chemicals become diluted, and costs are high.
In another method the raw sewage is sorted in a bag made of vinyl and the like to prevent the diffusion of the bad smell. This method however requires a vinyl bag of large size and involves high cost for disposal thereof, and is troublesome in separating the raw sewage from the bag.
In still another method the discharged raw sewage is directly dried by use of heat from a burner, etc. Since the primary component of raw sewage is liquid, it requires a large amount of heat energy to remove the liquid and it takes a long time to effect disposal of the raw sewage.
In view of the drawbacks of the conventional methods of disposing of the raw sewage, the present inventor proposed a drying apparatus having a casing provided with stirring blades and heating bodies therein in which the raw sewage is stirred by the rotation of the stirring blades and heated by heat generated by the heating bodies whereby the raw sewage is dried in a short period of time as disclosed in Japanese Patent Laid-Open Publication Nos. 63-124150, 63-172852, 63-190857, 63-292789 and Application No. 63-198858. However, according to the proposed disposing methods, an outer periphery of the casing storing the raw sewage is heated by the heat generated by the burner or the heat converted from electricity by a heater. Hence, the metal casing storing the raw sewage is first heated which entails inferior thermal efficiency.
Inasmuch as the conventional method is inferior in thermal efficiency, the direct heating of the raw sewage is superior in thermal efficiency. Hence, it is desired to proposed a disposing apparatus capable of heating the raw sewage by applying direct heat energy to the sewage.
It is an object of the present invention to provide a raw sewage drying apparatus capable of directly heating the raw sewage by applying a microwave to the liquid or materials to be heated, and hence the efficiency of heating the raw sewage is improved remarkably.
It is also an object of the present invention to provide a raw sewage drying apparatus capable of hygienically heating the raw sewage even if the raw sewage apparatus is installed in vehicles, vessels, etc.
It is a further object of the present invention to provide a raw sewage drying apparatus capable of heating the raw sewage by applying magnetic flux generated by high frequency or microwave generated by magnetron to the liquid, and the thickness of the casing is reduced to reduce the cost for manufacturing thereof.